diff --git a/src/ESPAsyncWebServer.h b/src/ESPAsyncWebServer.h
index 781fdb0..510fcac 100644
--- a/src/ESPAsyncWebServer.h
+++ b/src/ESPAsyncWebServer.h
@@ -295,13 +295,13 @@ class AsyncWebServerRequest {
 
     void send(AsyncWebServerResponse* response);
 
-    void send(int code, const char* contentType = "", const char* content = "", AwsTemplateProcessor callback = nullptr) { send(beginResponse(code, contentType, content, callback)); }
+    void send(int code, const char* contentType = asyncsrv::empty, const char* content = asyncsrv::empty, AwsTemplateProcessor callback = nullptr) { send(beginResponse(code, contentType, content, callback)); }
     void send(int code, const String& contentType, const String& content = emptyString, AwsTemplateProcessor callback = nullptr) { send(beginResponse(code, contentType, content, callback)); }
 
     void send(int code, const char* contentType, const uint8_t* content, size_t len, AwsTemplateProcessor callback = nullptr) { send(beginResponse(code, contentType, content, len, callback)); }
     void send(int code, const String& contentType, const uint8_t* content, size_t len, AwsTemplateProcessor callback = nullptr) { send(beginResponse(code, contentType, content, len, callback)); }
 
-    void send(FS& fs, const String& path, const char* contentType = "", bool download = false, AwsTemplateProcessor callback = nullptr) {
+    void send(FS& fs, const String& path, const char* contentType = asyncsrv::empty, bool download = false, AwsTemplateProcessor callback = nullptr) {
       if (fs.exists(path) || (!download && fs.exists(path + asyncsrv::T__gz))) {
         send(beginResponse(fs, path, contentType, download, callback));
       } else
@@ -309,7 +309,7 @@ class AsyncWebServerRequest {
     }
     void send(FS& fs, const String& path, const String& contentType = emptyString, bool download = false, AwsTemplateProcessor callback = nullptr) { send(fs, path, contentType.c_str(), download, callback); }
 
-    void send(File content, const String& path, const char* contentType = "", bool download = false, AwsTemplateProcessor callback = nullptr) {
+    void send(File content, const String& path, const char* contentType = asyncsrv::empty, bool download = false, AwsTemplateProcessor callback = nullptr) {
       if (content) {
         send(beginResponse(content, path, contentType, download, callback));
       } else
@@ -339,16 +339,16 @@ class AsyncWebServerRequest {
     void send(int code, const String& contentType, PGM_P content, AwsTemplateProcessor callback = nullptr) { send(beginResponse(code, contentType, content, callback)); }
 #endif
 
-    AsyncWebServerResponse* beginResponse(int code, const char* contentType = "", const char* content = "", AwsTemplateProcessor callback = nullptr);
+    AsyncWebServerResponse* beginResponse(int code, const char* contentType = asyncsrv::empty, const char* content = asyncsrv::empty, AwsTemplateProcessor callback = nullptr);
     AsyncWebServerResponse* beginResponse(int code, const String& contentType, const String& content = emptyString, AwsTemplateProcessor callback = nullptr) { return beginResponse(code, contentType.c_str(), content.c_str(), callback); }
 
     AsyncWebServerResponse* beginResponse(int code, const char* contentType, const uint8_t* content, size_t len, AwsTemplateProcessor callback = nullptr);
     AsyncWebServerResponse* beginResponse(int code, const String& contentType, const uint8_t* content, size_t len, AwsTemplateProcessor callback = nullptr) { return beginResponse(code, contentType.c_str(), content, len, callback); }
 
-    AsyncWebServerResponse* beginResponse(FS& fs, const String& path, const char* contentType = "", bool download = false, AwsTemplateProcessor callback = nullptr);
+    AsyncWebServerResponse* beginResponse(FS& fs, const String& path, const char* contentType = asyncsrv::empty, bool download = false, AwsTemplateProcessor callback = nullptr);
     AsyncWebServerResponse* beginResponse(FS& fs, const String& path, const String& contentType = emptyString, bool download = false, AwsTemplateProcessor callback = nullptr) { return beginResponse(fs, path, contentType.c_str(), download, callback); }
 
-    AsyncWebServerResponse* beginResponse(File content, const String& path, const char* contentType = "", bool download = false, AwsTemplateProcessor callback = nullptr);
+    AsyncWebServerResponse* beginResponse(File content, const String& path, const char* contentType = asyncsrv::empty, bool download = false, AwsTemplateProcessor callback = nullptr);
     AsyncWebServerResponse* beginResponse(File content, const String& path, const String& contentType = emptyString, bool download = false, AwsTemplateProcessor callback = nullptr) { return beginResponse(content, path, contentType.c_str(), download, callback); }
 
     AsyncWebServerResponse* beginResponse(Stream& stream, const char* contentType, size_t len, AwsTemplateProcessor callback = nullptr);
diff --git a/src/WebResponseImpl.h b/src/WebResponseImpl.h
index 21b9044..a6f71bb 100644
--- a/src/WebResponseImpl.h
+++ b/src/WebResponseImpl.h
@@ -28,6 +28,7 @@
 #endif
 #include <memory>
 #include <vector>
+#include "literals.h"
 
 // It is possible to restore these defines, but one can use _min and _max instead. Or std::min, std::max.
 
@@ -36,7 +37,7 @@ class AsyncBasicResponse : public AsyncWebServerResponse {
     String _content;
 
   public:
-    AsyncBasicResponse(int code, const char* contentType = "", const char* content = "");
+    explicit AsyncBasicResponse(int code, const char* contentType = asyncsrv::empty, const char* content = asyncsrv::empty);
     AsyncBasicResponse(int code, const String& contentType, const String& content = emptyString) : AsyncBasicResponse(code, contentType.c_str(), content.c_str()) {}
     void _respond(AsyncWebServerRequest* request);
     size_t _ack(AsyncWebServerRequest* request, size_t len, uint32_t time);
@@ -80,9 +81,9 @@ class AsyncFileResponse : public AsyncAbstractResponse {
     void _setContentTypeFromPath(const String& path);
 
   public:
-    AsyncFileResponse(FS& fs, const String& path, const char* contentType = "", bool download = false, AwsTemplateProcessor callback = nullptr);
+    AsyncFileResponse(FS& fs, const String& path, const char* contentType = asyncsrv::empty, bool download = false, AwsTemplateProcessor callback = nullptr);
     AsyncFileResponse(FS& fs, const String& path, const String& contentType, bool download = false, AwsTemplateProcessor callback = nullptr) : AsyncFileResponse(fs, path, contentType.c_str(), download, callback) {}
-    AsyncFileResponse(File content, const String& path, const char* contentType = "", bool download = false, AwsTemplateProcessor callback = nullptr);
+    AsyncFileResponse(File content, const String& path, const char* contentType = asyncsrv::empty, bool download = false, AwsTemplateProcessor callback = nullptr);
     AsyncFileResponse(File content, const String& path, const String& contentType, bool download = false, AwsTemplateProcessor callack = nullptr) : AsyncFileResponse(content, path, contentType.c_str(), download, callack) {}
     ~AsyncFileResponse();
     bool _sourceValid() const { return !!(_content); }
diff --git a/src/literals.h b/src/literals.h
index c60a3eb..8a7293b 100644
--- a/src/literals.h
+++ b/src/literals.h
@@ -2,6 +2,8 @@
 
 namespace asyncsrv {
 
+static constexpr const char* empty = "";
+
 #ifndef ESP8622
 static constexpr const char* T_100_CONTINUE     = "100-continue";
 static constexpr const char* T_ACCEPT           = "Accept";